Should be fine. It wouldn't hurt to put in some MelaFix in. It has tea tree oil in it and helps the fish heal surface injuries like that. My oscar jumps all the time and bonks himself on the lights, and also fights with his pleco roomie. Unless there's obvious bleeding or you see swelling and infection start to become a problem, your fish should be fine on his own. Just tell people he's going bald and when they say "I didn't know fish did that" tell them there's a LOT about fish they don't know and act all smart and stuff.